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Uptake of paralytic shellfish toxins by blacklip abalone (Haliotis rubra rubra Leach) from direct exposure to Alexandrium catenella microalgal cells and toxic aquaculture feed

journal contribution
posted on 2023-05-20, 18:55 authored by Andreas SegerAndreas Seger, Gustaaf HallegraeffGustaaf Hallegraeff, Stone, DAJ, Bansemer, MS, Harwood, DT, Alison TurnbullAlison Turnbull

The Tasmanian abalone fishery represents the largest wild abalone resource in the world, supplying close to 25% of the annual wild-caught global harvest. Prompted by the need to manage Paralytic Shellfish Toxin (PST) contamination of Blacklip Abalone (Haliotis rubra rubra) from east coast Tasmania, the uptake of toxins by this species is investigated in a land-based, controlled aquaculture setting. Abalone were exposed to either live Alexandrium catenella microalgal cultures or PST contaminated feed pellets during a 28 day exposure period and toxins quantified in viscera, foot muscle and epipodium tissues. PST profiles of abalone foot tissues were dominated by saxitoxin and neosaxitoxin, whilst viscera more closely resembled those of the toxin source (A. catenella cells rich in gonyautoxin 1&4 and 2&3 or feed pellets containing A. catenella extracts rich in these analogues). This indicates direct uptake of PST in the viscera via browsing/grazing on the pellet and /or sedimented microalgal cells. After exposure to A. catenella cell culture, PST concentrations in the foot (muscle + epipodium) were on average 8 times higher than in the viscera. Higher toxicity of foot tissue was caused by higher PST content of the epipodium (up to 1,085 µg STX.2HCl equiv. kg−1), which despite its small contribution to total animal weight significantly added to the overall toxin burden. Higher PST levels in the abalone foot suggest that toxin monitoring programmes may not need to routinely analyse both foot and viscera, potentially allowing for a 50% reduction of analytical costs. This option is being further investigated with continuing field studies.

Funding

Fisheries Research & Development Corporation

History

Publication title

Harmful Algae

Volume

99

Article number

101925

Number

101925

Pagination

1-9

ISSN

1568-9883

Department/School

Institute for Marine and Antarctic Studies

Publisher

Elsevier Science Bv

Place of publication

Netherlands

Rights statement

Copyright 2020 Crown Copyright

Repository Status

  • Restricted

Socio-economic Objectives

Wild caught edible molluscs; Fish product traceability and quality assurance; Control of pests, diseases and exotic species in coastal and estuarine environments